Climate

US Gov't Report Confirms 2016 Was the Hottest Year on Record

In their annual State of the Climate report, the National Oceanic and Atmospheric Administration and the American Meteorological Society said that carbon dioxide concentrations are the highest they've been in 800,000 years.

The symptoms of man-made climate change showed up all over the planet in 2016, and there’s no sign the planet’s fever will break anytime soon as record concentrations of greenhouse gases build up in the atmosphere.

That’s the diagnosis of the National Oceanic and Atmospheric Administration and the American Meteorological Society, which released their annual State of the Climate report Thursday. From shriveled icecaps at the poles to deadly heat waves in the tropics, deep droughts on every continent, and warmer oceans and lakes, the signs of human-driven warming were everywhere.

The past year was the warmest on record, and the third straight year a record was set. It was the second year global average temperatures ran 1 degree Celsius (1.8 degrees Fahrenheit) over pre-industrial times — halfway to the mark where the Paris climate accord hopes to halt warming by 2100.

That warming is being driven by human emissions of carbon dioxide, methane, and other gases, all of which grew in 2016, said NOAA climatologist Jessica Blunden, the report’s lead editor.

“They all continued to increase, and they all reached new record highs,” Blunden said.

The report is a sort of annual checkup on the Earth, compiled by NOAA and the American Meteorological Society out of data from researchers in 64 countries.

Atmospheric CO2 readings jumped by the largest percentage on record, with the annual average concentration topping 400 parts per million for the first time. That’s not only a record in modern observations, but more than has been found in ice cores dating back 800,000 years.

Nearly a third of the Earth’s land area was hit by drought in 2016. About 16 percent of the land was in severe or extreme drought — an area comparable to the size of Russia, said Robert Dunn, a climate scientist at the Met Office, the British weather agency.

Temperatures in places like India and the Middle East spiked to extremes rarely seen before. Mercury poked about 50°C (122°F) in Iran, Iraq, and Kuwait during 2016, Dunn said.

The far North continued to warm at a much faster pace than the rest of the globe. The Arctic is about 3.5°C (6.5°F) warmer than it was in 1900, eating away at sea ice, glaciers, and the massive ice sheet over Greenland. “The effects of warming are cascading through the ecosystem and the environment like we’ve ever seen before,” said Jeremy Mathis, the head of NOAA’s Arctic Research Program.

And while the data amassed this year isn’t as extensive as what went into Thursday’s report, 2017’s temperatures appear to be running somewhere close to the highs clocked in recent years, said Deke Arndt, chief of the climate monitoring branch at NOAA's National Centers for Environmental Information.

“I think it is safe to say it is likely to finish among the three warmest overall for the year,” Arndt said.

President Donald Trump has called climate change a "hoax" and "bullshit" and complained that the Paris agreement was a bad deal for the United States. His administration has announced plans to roll back the centerpiece of his predecessor’s carbon-reduction plans and proposed deep cuts in the budgets of federal science agencies and the Environmental Protection Agency.

Arndt said the document “is a diagnostic report,” meant to provide intelligence to US policymakers. But he said the trends are consistent over the past several decades — and while the effects won’t fall evenly around the world, the net costs are likely to outweigh the benefits.

Despite the new administration’s rhetoric, a draft of the upcoming National Climate Assessment — a document the White House produces every four years — states that climate is changing “at a pace and in a pattern not explainable by natural influences.” Average annual temperatures in the United States are already about a degree C higher than they were throughout most of the 20th century, according to a New York Times report about the draft document.

And the world’s other leading sources of greenhouse gases have reaffirmed their commitment to the Paris pact and its 2°C target — a threshold beyond which scientists warn climate change could have catastrophic consequences.